Cytological and Microbiological Study of the External Ear Canal in Dogs With Atopic Dermatitis

Background: Otitis externa is the most important disease of the external ear canal. Canine atopic dermatitis (CAD) is a pruritic and inflammatory skin disease with a genetic background. Otitis externa is common in dogs and many of these cases are related to atopy. Objectives: In this study, by comparing the characteristics of the external ear canal of atopic and non-atopic dogs with otitis, we aimed to determine their cytological and microbiological patterns and guide clinicians in choosing the best diagnostic and treatment plans. Methods: Twenty atopic and 26 non-atopic dogs were studied. Atopy was diagnosed based on history and clinical examination findings according to Favrot’s criteria. Sampling was performed from the external ear canal. The signalment of the cases was recorded and analyzed, along with cytological and microbiological features. Results: Microscopic and macroscopic studies of the external ear canal showed no statistically significant difference between groups. In addition, the most frequent bacterial isolate cultured was Staphylococcus pseudintermedius in both groups, with a frequency of 69.5%. The genera Pseudomonas, Escheria and Streptococcus followed, with frequencies of 17.4%, 10.9% and 7.8%, respectively. Conclusion: The results of our study are largely consistent with those of previous studies that evaluated the external ear canal of dogs with otitis. According to our findings, the features of the inflamed ear canal did not differ significantly between atopic and non-atopic patients.